JPS6254838A - Suspension spring for objective lens of optical pickup device and its production - Google Patents

Abstract

PURPOSE:To prevent the ill effect of the resonance of suspension springs on reproduction signal by packing a damping material between plural plate conductors so as to attenuate the resonace of the plate conductorss. CONSTITUTION:The tow plate conductors 9i constituting the respective suspension springs 9e and 9f are different in width and resonance frequency from each other so that the suspension sprints 9e and 9f are made difficulty resonatable at the specific frequency and that the unnecessary resonance is thereby made hardly generatable. The effect is higher when the plate conductor 9i having the larger width is disposed on the outside. The damping material 9m consisting of viscoelastic material such as butyl rubber or silicone rubber is packed between the tow plate conductors 9i of the suspension springs 9e and 9f, by which the resonance generated in the plate conductorss 9i is attenuated.

Description

[Detailed description of the invention] [Industrial application field]

The present invention relates to a suspension spring that swingably supports an objective lens in an optical pickup device used in a video disc player, a compact disc player, etc., and a method for manufacturing the suspension spring. Summary of the Invention In an optical pickup device, a suspension spring that swingably supports an objective lens for focus control and tracking control is connected to a plurality of plate-shaped conductors each arranged in parallel to the plate. They are each made of a dump material made of a viscoelastic material filled between conductors by silk screen printing, and are formed in large numbers on a single sheet at the same time. There is also a process of forming a large number of suspension springs, each consisting of a plurality of plate-shaped conductors arranged in parallel, on a sheet by etching, and a pattern that passes only between the plate-shaped conductors by silk screen printing on the sheet. This manufacturing method includes the steps of: applying a damping material made of a viscoelastic material using a viscoelastic material; and vulcanizing the damping material. [Prior Art] Conventionally, in an optical pickup device, an objective lens is swingably supported by two sets of suspension springs provided on each side of the objective lens, and a focusing coil and a tracking coil fixed to the objective lens are driven. It is known that the objective lens is moved parallel to the optical axis to perform focus control and tracking l1tlD. However, such a device has the disadvantage that all the suspension springs resonate at a specific frequency, which causes noise to be mixed into the reproduced signal. "Problems to be Solved by the Invention" The purpose of the present invention is to improve the drawbacks of the above-mentioned conventional devices, and to provide a suspension spring that does not generate unnecessary resonance. An object of the present invention is to provide a manufacturing method for manufacturing a large number of suspension springs at the same time.Means for Solving Problem K] In order to achieve the above object, a suspension spring for an objective lens of an optical pickup device of the present invention is provided. Each of these is composed of a plurality of plate-shaped conductors arranged in parallel and a dump material made of a viscoelastic material filled between the plate-shaped conductors by silk screen printing. The manufacturing method includes (a) etching a number of suspension springs each made of a plurality of plate-shaped conductors arranged in parallel on a sheet, and (b) etching the suspension springs on the sheet. The method consists of a step of applying a damping material made of a viscoelastic material using a pattern that passes only between the plate-shaped conductors by silk screen printing, and (c) a step of vulcanizing the damping material.

[Effect]

By doing this, the damping material filled between the plurality of plate-shaped conductors that make up each suspension spring damps the resonance of each plate-shaped conductor, which prevents unnecessary resonance from occurring in the suspension spring and improves the reproduction signal. In addition, a large number of suspension springs can be formed simultaneously on one sheet. K Embodiment An optical pickup device which is an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a plan view and a front view thereof, and FIG.
The figure is a plan view (partial partial view) showing the part where the base 10 in which the actuator 9 is integrated is removed.
It is. The optical pickup device includes a laser diode 2, a grating 3, and a plate prism 4 built into a body 1.
, a collimator lens 5, a triangular prism 6, a multi-lens 7, a photodetector 8, and an actuator 9 built into a base 10. FIG. 3 is an explanatory diagram showing the optical path. In order to display on the same plane, the triangular prism 6, objective lens 9a, and disk D are arranged at 90 degrees centering on the optical axis in the left and right direction in the figure.
'Shown in a twisted position. The laser beam emitted from the laser diode 2 is reflected by the plate prism 4 and the triangular prism 6, focused by the objective lens 9a, and focused on the signal recording surface of the disk D located above the optical backup device, where it is recorded. The reflected light modulated by the signal is reflected again by the triangular prism 6, passes through the plate prism 4 and the multi-lens 7, is given astigmatism, and is guided to the photodetector 8. The plate prism 4 has a half mirror 4a made of a thin metal film formed on one surface of a glass plate with parallel planes.
The laser beam emitted from the laser diode 2, which is arranged at an angle of approximately 45 degrees with respect to the optical axis, is reflected by this half mirror 4a toward the triangular prism 6, and conversely sent from the triangular prism 6 ( The reflected light (modulated by the signal recording surface of the disk D) passes through the plate prism 4 and is sent to the multi-lens 7. The reflected light from the signal recording surface of the disk D passes through the plate prism 4.
Astigmatism is applied when passing through the light. The multi-lens 7 is a combination of a concave lens and a cylinder lens, and provides astigmatism (in a direction different from that of the plate prism 4) to transmitted light, as well as (by moving its position in the optical axis direction). Change the convergence position of transmitted light. The photodetector 8 is composed of a focus detector consisting of four photodetecting elements divided by two orthogonal straight lines and a pair of tracking detectors placed on both sides of the focus detector, and the detection signals of these rain detectors are detected by the objective lens. It is input to the actuator 9 as a signal for the drive vJυ11III of the drive signal 9a. The direction in which astigmatism, which is the combination of the astigmatism given by the plate prism 4 and the multi-lens 7, occurs is set so that the direction in which the sensitivity of the focus detector of the photodetector 8 is maximum is set, and the disc D In order to eliminate the influence of the shadow of the recording track on focus detection,
The direction of the recording track is set to match the direction of one dividing line of the focus detector. By adjusting the position of the multi-lens 7 in the optical axis direction and in the plane orthogonal to the optical axis so that the light beam transmitted through the plate prism 4 enters the photodetector 8 correctly (with the photodetector 8 fixed), the light is It is designed to perform axis alignment and focus adjustment. FIG. 4 shows a support mechanism for the multi-lens 7. The multi-lens 7 is fixed within a lens sleeve 7b having a groove 7a in the circumferential direction.
is supported in a lens base 7d having a pair of wing parts IC so as to be slidable in the axial direction thereof but not rotated. As shown in FIG. 2, the lens base 7d has its pair of wing parts 7C held between the positioning part 1a of the body 1 and the elastic base presser 1b, and is thereby moved in a plane perpendicular to the optical axis. Possibly supported. The tips of the wing portions 7C of the lens base 7d face windows 1C formed on both sides of the body 1, and when aligning the optical axis, the wing portions 7C are held between the windows 1C using a jig. Then, the position is adjusted within a plane perpendicular to the optical axis. Further, when adjusting the focus, an eccentric bottle is inserted through a hole formed on the back surface of the body 1 and the lens base 7d, and the eccentric bottle is engaged with the groove 7a of the lens sleeve 7b and rotated. Adjustment is made by changing the position of the lens sleeve 7b in the optical axis direction. The plate prism 4 is adhesively fixed to the positioning portion 1d of the body 1 on the surface on which the half mirror 4a is provided, and is also fixed at a small interval on both ends of the plate prism 4 and on the surface opposite to the half mirror 4a. Four protrusions 11a are arranged to prevent movement. As shown in FIG.
Used for temporary positioning when installing. As shown in FIG. 2, a G holder 38 that supports the grating 3 and the laser diode 2 are mounted in a hole 1e formed in a protrusion on the side surface of the body 1. The G holder 3a is positioned by bringing its front surface into contact with the first step 1f in the mounting hole 1e, and the G holder 3a is positioned between the rear surface and the base of the laser diode 2.
It is pressed forward by a spring 3b and supported so as to be rotatable and adjustable around the optical axis. Laser diode 2 is mounted on the shoulder of its base through hole 1.
It is positioned by coming into contact with the second step 1g in e, and its rear surface is pressed and supported by the LD presser 12. The LD presser 12 has two elastic legs each having an engaging claw 12a at the tip, and connects the two engaging claws 12a with two elastic legs formed at corresponding positions on the outer periphery of the protrusion of the body. They are respectively engaged with the engaging portions 1h. When installing the G holder 3a and the laser diode 2, insert the G holder 3a, washer, G spring 3b, and laser diode 2 into the hole 1e in this order, and attach the LD to the rear surface of the base of the laser diode 2. The presser foot 12 is brought into contact and pressed, and the engaging claws 1 of the two elastic legs are pressed.
2a are respectively engaged with the engaging portions 1h of the body 1 by the elasticity of the elastic legs. The laser diode 2 is very susceptible to static electricity and easily damaged, but if it is damaged, the engaging claw 1 of the LD presser 12
2a from the engaging portion 1h of the body 1 and removing the LD presser 12, the laser diode 2 can be easily replaced as a single unit. The collimator lens 5 has two legs 5b and 5C on the back side.
The two legs 5b and 5C are supported by a collimator holder 5a having a
are fitted into positioning round holes 11, respectively. The shape of the cross section perpendicular to the axis of the two legs 5b and 5C is
One leg 5b has a circular shape, and the other leg 5C has an elliptical or diamond shape that is long in the direction of the optical axis and short in the direction orthogonal to the optical axis, and the leg 5C is shaped like an optical axis within the round hole 11. It can be moved slightly in the orthogonal direction, thereby allowing a certain degree of dimensional error (between the distance between the legs and the distance between the round holes in the direction perpendicular to the optical axis) while maintaining high positioning accuracy in the direction of the optical axis. It looks like this. FIG. 7 shows an exploded perspective view of the actuator 9 that swingably supports the objective lens 9a and performs focus control and tracking control. The actuator 9 is integrated into the base 10 so that the objective lens 9a is located above the triangular prism 6 when the base 10 is attached to the body 1. The positioning of the base 10 with respect to the body 1 is performed by fitting the round bottles and diamond bottles protruding from the base 10 into round holes provided in the pickup body, in the same manner as the positioning of the collimator holder 5a shown in FIG. It is carried out in The actuator 9 includes a flange 9d to which an objective lens 9a, a focus coil 9b, and two tracking coils 9C are fixed, and a projection 10 of a base 10 that connects the flange 9d.
It is composed of two sets of suspension springs 9e and 9'' on the left and right sides that are swingably supported on the base 10, and a magnet 9g and a yoke 9h that are fixed to the base 10. The magnet 9g is located on the side facing the coil. It has a trapezoidal shape whose width is wider than that of the opposite side, and in order to make the CD player smaller, the pickup P is arranged so as to move in the diagonal direction of the CD player, as shown in FIG. Also, if the outer corner of the magnet side of the pickup P is cut diagonally (to avoid hitting the wall of the CD player), even if the flange 9d is wide left and right (for tracking), both sides will be cut off. The tracking coil 9c (inner vertical part) of the tracking coil 9c is made to not come off the surface of the magnet 9g. Note that it is sufficient that the magnet 9g has a shape in which at least the outer corner of the magnet 9g is shaved. It goes without saying that its shape is not limited to an isosceles trapezoid, but may also be an isosceles trapezoid in which the outer circumferential side is more inclined than the inner circumferential side.When performing focus control and tracking control by driving the objective lens 9a In order to keep the attitude of the objective lens 9a parallel to the optical axis, the flange 9d is supported by two sets of suspension springs 9e and 9f, which are arranged in parallel with each other, at vertically spaced intervals on both the left and right sides of the flange 9d. A total of 4 sets of suspension springs 9e and 9f on the left and right sides
As shown in FIG. 9, the flange 9 has a shape in which terminals 9j for attachment are provided at both ends of two elongated elastic plate-shaped conductors 91 arranged in parallel.
d and also serves as a lead wire for sending control signals to the focus coil 9b and the tracking coil 9C. As shown in the figure, the upper and lower suspension springs 9e and 9f on one side are integrally manufactured in a shape in which the terminals 9j on both sides thereof are connected by two claw portions 9k through narrow connection portions. When installing, connect the terminals 9j on both sides to the protrusion '10a of the base 10 and the flange 9d.
After fixing the upper and lower suspension springs 9e and 9f with adhesive, the two claws 9k are broken off to electrically separate the upper and lower suspension springs 9e and 9f. The screws 9e and 9 can be attached accurately in parallel. The two plate-shaped conductors 91 constituting each suspension spring 9e and 9f have different widths (for example, 0
．． 10mm and 0.12I1w>Due to the difference in resonance frequency, suspension springs 9e and 9f are less likely to resonate at a specific frequency, thereby making it less likely that unnecessary resonance will occur. In addition, in this case, it is more effective to place the wider plate-shaped conductor 91 on the outside (that is, on the upper side in 9e, and on the lower side in 9''). In addition, a damping material 9IIl made of a viscoelastic material such as butyl rubber or silicone rubber is filled between the two plate-shaped conductors 91 of the suspension springs 9e and 9f, and this causes The suspension springs are designed to attenuate resonance. The manufacturing process of the suspension springs will be explained with reference to FIGS. In the connected state, a large number of etches are simultaneously formed on one sheet 13 by etching.After this sheet 13 is thoroughly washed, a brimer is applied, and as shown in FIG. 14, apply 9m of dumping material using a pattern that passes through only the dumping material 9IIl part, and finally, ■ Temperature 200
The dump material 9II+ was baked by vulcanization at ℃ for 15 minutes. 9m of dump material is coated with brimer as a pre-treatment.
This is to make it easier to adhere. When applying the dump material 9I11 using the silk screen printer 14, a printing brush is moved in the longitudinal direction of the plate-shaped conductor 91. Furthermore, if 9m of dump material is mixed with 9n of scale-like particles (for example, scaly graphite, mica, etc.) with a size of several μm to several tens of μm, this will cause the two plate-like conductors 91
The effect of the so-called book damper becomes stronger, and the "shear damping" effect becomes larger. Furthermore, by using silk screen printing,
As shown in FIG. 12, the scale-like particles 9n are distributed in the moving direction of the printing brush (ie, in the longitudinal direction of the plate-shaped conductor 91).
Since they are aligned facing the same direction, the "shear damping" effect becomes even greater. In addition, in the above embodiment, each suspension spring 9e
, t5 and 9", the number of plate-shaped conductors 91 is set to two, but the number is not limited to this, and the number may be three or more. Effects of the Invention] As explained above. In the suspension spring for the objective lens of the optical pickup device of the present invention, the damping material filled between the plurality of plate-shaped conductors attenuates the resonance of the plate-shaped conductors, thereby suppressing unnecessary resonance of the suspension spring. can prevent negative effects on the playback signal,
Furthermore, the manufacturing method allows a large number of suspension springs to be formed simultaneously on one sheet.

[Brief explanation of the drawing]

Fig. 1: A plan view and front view of an embodiment of the invention Fig. 2: A plan view with the cover removed Fig. 3:
...An explanatory diagram showing the optical path.FIG. 4.A perspective view showing the multi-lens support mechanism.FIG. 5.A perspective view of the back cover.FIG. 6.An explanation showing the collimator lens positioning means. Figure 7: Exploded perspective view of the actuator Figure 8:
・・Plan view showing its arrangement in a CD player FIG. 9 ・Plan view of the suspension spring FIG. 10 ・・Plan view of one manufacturing process of the suspension spring FIG. 11 ・・Silk screen of the suspension spring Side view showing printing FIG. 121...Explanatory diagrams of damping agent for the suspension spring 9e, 9f...Suspension spring 91...Plate conductor 9m...Damp material 13...Sheet

Claims (2)

[Claims] (1) Each conductor is composed of a plurality of plate-shaped conductors formed in large numbers on a sheet by etching and arranged in parallel, and a dump material made of a viscoelastic material filled between the plate-shaped conductors by silk screen printing. A suspension spring for an objective lens of an optical pickup device. (2) (a) forming a large number of suspension springs each consisting of a plurality of plate-shaped conductors arranged in parallel on a sheet by etching, and (b) forming the plate-shaped conductors by silk screen printing on the sheet; For use in an objective lens of an optical pickup device, comprising the steps of: applying a damping material made of a viscoelastic material using a pattern that allows only the intervening portion to pass; and (c) vulcanizing the damping material. How to manufacture suspension springs.